Laser processing device and laser processing method

Abstract

The laser processing apparatus of the present invention includes a holding section, a light source, a moving section, and a control section. The holding section holds a substrate formed by slicing a single-crystal ingot. The light source oscillates laser light irradiating a first major surface of the substrate. The moving section moves the position of the laser light irradiation point on the first major surface of the substrate while the substrate is held in the holding section. The control section controls the removal of the surface layer across the entire first major surface of the substrate by controlling the light source and the moving section.

Description

Technical Field

[0001] This invention relates to a laser processing apparatus and a laser processing method. Prior Technology

[0002] Patent document 1 discloses a method for processing semiconductor wafers. This method involves performing chamfering, polishing, etching, and mirror polishing steps on semiconductor wafers obtained by slicing single-crystal ingots. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2002-203823 Summary of the Invention

[0004] [The problem that the invention aims to solve] One aspect of the present invention is to provide a technique for "removing debris attached to a substrate during the slicing of a single crystal ingot and suppressing the occurrence of substrate defects caused by the debris". [Methods for solving problems]

[0005] According to one aspect of the present invention, a laser processing apparatus includes a holding section, a light source, a moving section, and a control section. The holding section holds a substrate formed by slicing a single-crystal ingot. The light source oscillates laser light irradiating a first primary surface of the substrate. The moving section moves the position of the laser light irradiation point on the first primary surface of the substrate while the substrate is held in the holding section. The control section controls the removal of the surface layer across the entire first primary surface of the substrate by controlling the light source and the moving section. [Invention Effects]

[0006] Through one aspect of the present invention, debris adhering to the substrate during the slicing of a single crystal ingot can be removed, and defects in the substrate caused by such debris can be suppressed. Simple Explanation of the Diagram

[0007] Figure 1 is a plan view of a laser processing apparatus according to an embodiment. Figure 2 is a front view of the laser processing device shown in Figure 1. Figure 3(A) is a side view of an example of a substrate before laser processing, and Figure 3(B) is a side view of an example of a substrate after laser processing. Figure 4 is a flowchart illustrating a laser processing method according to an implementation example. Figure 5 is a diagram showing one example of an undulation measurement module. Figure 6 is a diagram showing one example of a laser processing module. Figure 7(A) is a diagram showing the first example of the intensity distribution of laser light, and Figure 7(B) is a diagram showing the second example of the intensity distribution of laser light. Figure 8(A) is a plan view showing the first example of the arrangement of the illumination points, Figure 8(B) is a plan view showing the second example of the arrangement of the illumination points, and Figure 8(C) is a plan view showing the third example of the arrangement of the illumination points. Implementation

[0008] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in each drawing, the same symbol is used to denote the same component, and explanations are omitted where appropriate. In this specification, the X-axis, Y-axis, and Z-axis are mutually perpendicular directions. The X-axis and Y-axis are horizontal directions, and the Z-axis is a vertical direction.

[0009] First, referring to Figures 1 and 2, the laser processing apparatus 1 according to this embodiment will be described. The laser processing apparatus 1 performs laser processing on a substrate W formed by slicing a single crystal ingot.

[0010] The substrate W is a silicon wafer or a compound semiconductor wafer. The compound semiconductor wafer is not particularly limited, and can be, for example, a GaAs wafer, SiC wafer, GaN wafer, or InP wafer. The substrate W is a bare wafer.

[0011] As shown in Figure 3(A), the substrate W includes a first major surface Wa and a second major surface Wb opposite to the first major surface Wa. The first major surface Wa and the second major surface Wb are formed by slicing a single crystal ingot. During slicing, debris may adhere to the first major surface Wa and the second major surface Wb. The debris may be, for example, abrasive grains from a cutting tool.

[0012] As shown in Figure 3(B), the laser processing apparatus 1 removes the surface layer Wa1 across the entire first principal surface Wa of the substrate W, and removes the surface layer Wb1 across the entire second principal surface Wb of the substrate W. This removes debris that adheres to the substrate W during the slicing of the single crystal ingot and suppresses the occurrence of defects in the substrate W caused by such debris.

[0013] As shown in Figure 1, the laser processing device 1 includes a transfer station 2, a processing station 3, and a control module 9. The transfer station 2 and the processing station 3 are arranged in this order along the positive X-axis.

[0014] The inbound / outbound station 2 is equipped with a loading platform 20 and a transport unit 23. The loading platform 20 has a plurality of loading plates 21. The plurality of loading plates 21 are arranged in a row in the Y-axis direction. A box C is placed on each of the plurality of (e.g., 3) loading plates 21. One box C holds a plurality of substrates W before processing. Another box C holds a plurality of substrates W after processing. The remaining box C holds a plurality of substrates W that have malfunctioned during processing. Furthermore, the number of loading plates 21 and the number of boxes C are not particularly limited.

[0015] The transport unit 23 is adjacent to the positive X-axis side of the mounting stage 20 and adjacent to the negative X-axis side of the processing station 3. The transport unit 23 has a transport arm 24 for holding the substrate W. The transport arm 24 can move in the horizontal direction (both X-axis and Y-axis directions) and the vertical direction, and rotate about the vertical axis. The transport arm 24 transports the substrate W between the cassette C on the mounting stage 20 and the third processing block G3 of the processing station 3.

[0016] Processing station 3 comprises a first processing block G1, a second processing block G2, a third processing block G3, a fourth processing block G4, and a transport block G5. The transport block G5 is located within the area enclosed by the first processing block G1, the second processing block G2, the third processing block G3, and the fourth processing block G4. The third processing block G3 is adjacent to the transport block G5 on the negative X-axis side.

[0017] The transport block G5 is equipped with a transport arm 38 for holding the substrate W. The transport arm 38 can move in the horizontal direction (both the X-axis and Y-axis directions) and the vertical direction, and rotate about the vertical axis. The transport arm 38 transports the substrate W between the first processing block G1, the second processing block G2, the third processing block G3 and the fourth processing block G4.

[0018] The first processing block G1 is disposed adjacent to the positive Y-axis side of the transport block G5. The first processing block G1, for example, has a laser processing module 31. The laser processing module 31 irradiates laser light onto the first main surface Wa of the substrate W, covering the entire first main surface Wa to remove the surface layer Wa1. Furthermore, the laser processing module 31 irradiates laser light onto the second main surface Wb of the substrate W, covering the entire second main surface Wb to remove the surface layer Wb1. The surface layers Wa1 and Wb1 absorb the laser light and either change from a solid phase to a gaseous state and disperse, or remain solid and disperse.

[0019] The second processing block G2 is adjacent to the negative Y-axis side of the transport block G5. The second processing block G2 includes, for example, a cleaning module 32 and an etching module 33. The cleaning module 32 cleans the substrate W by brushing and removing debris scattered from the laser irradiation point. The etching module 33 etches the substrate W to reduce its surface roughness or remove the discoloration layer formed by laser irradiation. The cleaning module 32 is not required when debris removal is not necessary. Similarly, the etching module 33 is not required when surface roughness reduction or discoloration layer removal is not necessary. The arrangement of the cleaning module 32 and the etching module 33 is not limited to the arrangement shown in Figure 2.

[0020] The third processing block G3 is adjacent to the negative X-axis side of the transport block G5. As shown in Figure 2, the third processing block G3 includes, for example, a transfer module 34, an undulation measurement module 35, and a flipping module 36. The transfer module 34 transfers the substrate W between the transport arm 24 of the transport station 2 and the transport arm 38 of the processing station 3. The undulation measurement module 35 measures the undulation of the first major surface Wa of the substrate W. Also, the undulation measurement module 35 measures the undulation of the second major surface Wb of the substrate W. The undulation measurement is performed using a commercially available three-dimensional shape measuring instrument, etc. The flipping module 36 flips the substrate W. The arrangement of the transfer module 34, the undulation measurement module 35, and the flipping module 36 is not limited to the arrangement shown in Figure 2.

[0021] The fourth processing block G4 is disposed adjacent to the positive X-axis side of the transport block G5. The fourth processing block G4, for example, has a polishing module 37. The polishing module 37 polishes the first main surface Wa of the substrate W, improving the flatness of the first main surface Wa. Also, the polishing module 37 polishes the second main surface Wb of the substrate W, improving the flatness of the second main surface Wb. Furthermore, if sufficient flatness can be obtained through laser irradiation, the polishing module 37 is not required.

[0022] Furthermore, the processing station 3 may have at least a laser processing module 31. The type, configuration, and number of modules constituting the processing station 3 are not limited to those shown in Figures 1 and 2.

[0023] The control module 9 is, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a recording medium 92 containing memory. The recording medium 92 stores programs that control the various processes performed in the laser processing apparatus 1. The control module 9 controls the operation of the laser processing apparatus 1 by having the CPU 91 execute the programs recorded on the recording medium 92.

[0024] Next, referring to Figure 4, the laser processing method according to this embodiment will be described. Steps S101 to S109 shown in Figure 4 are performed under the control of the control module 9.

[0025] First, the transport arm 24 of the loading station 2 removes the substrate W from the cassette C on the platform 20 and transports it to the transfer module 34. Next, the transport arm 38 of the processing station 3 receives the substrate W from the transfer module 34 and transports it to the undulation measurement module 35. During this process, the substrate W is held horizontally with its first primary surface Wa facing upwards.

[0026] Next, the undulation measurement module 35 measures the undulation of the first major surface Wa of the substrate W (step S101). The undulation measurement is performed in a natural state where no external force other than gravity and its resistance, such as adsorption force, is applied. The natural state is a state in which the substrate W is not deformed and the stress on the substrate surface is substantially zero. For example, as shown in FIG5, the undulation measurement is performed with the substrate W simply placed on the horizontal surface of the stage 35a. The undulation measurement module 35 has a displacement meter 35b. The displacement meter 35b measures the height distribution of the top surface (e.g., the first major surface Wa) of the substrate W. In this embodiment, the displacement meter 35b is non-contact, but it could also be contact. The undulation measurement module 35 transmits its measurement data to the control module 9. After the above step S101, the transport arm 38 removes the substrate W from the undulation measurement module 35 and transports it to the laser processing module 31.

[0027] Next, the laser processing module 31 performs laser processing on the first main surface Wa of the substrate W (step S102). Specifically, as shown in FIG6, the laser processing module 31 irradiates the first main surface Wa with laser light LB, and moves the position of the irradiation point P to cover the entire first main surface Wa, thereby removing the surface layer Wa1.

[0028] During the slicing of a single-crystal ingot, debris can adhere to the surface layer Wa1. If the substrate W is ground (including polished) while the debris is still attached, the debris will be pushed onto the substrate W, creating defects. These defects may be amplified by subsequent etching.

[0029] By removing the surface layer Wa1, debris attached to the surface layer Wa1 can be removed. Furthermore, by removing the surface layer Wa1, debris that cannot be removed by brushing or other methods can also be removed. Therefore, defects on the substrate W caused by debris can be suppressed.

[0030] Furthermore, the laser processing module 31 can reduce the undulation of the first primary surface Wa when removing the surface layer Wa1. The removal amount is controlled by the product of the output power of the laser light LB (unit: W) and the irradiation time, i.e., the cumulative irradiation amount (unit: J). The greater the cumulative irradiation amount, the greater the removal amount.

[0031] The control module 9 refers to the measurement data of the fluctuation measurement module 35 to control the cumulative irradiation of the laser light LB per unit area of ​​the first primary surface Wa, so as to reduce the fluctuation of the first primary surface Wa. The control system includes one or more of the following: control of the output power of the light source 31b and control of the irradiation time.

[0032] If the substrate W is pressed onto a platform for polishing in order to reduce the undulation of the first primary surface Wa, the substrate W will elastically deform. Therefore, it is difficult to reduce the undulation of the substrate W. Furthermore, debris will be pushed onto the substrate W, creating defects on the substrate W.

[0033] Through this embodiment, since the control module 9 controls the cumulative irradiance per unit area by referring to the measurement data of the fluctuation of the first primary surface Wa under natural conditions, the fluctuation can be reduced efficiently and the surface can be corrected efficiently.

[0034] The laser processing of the first primary surface Wa is performed in a natural state, such as simply placing the substrate W on the horizontal surface of the stage 31a. Even if there are foreign objects between the substrate W and the stage 31a, the foreign objects will not be pushed onto the substrate W, and no defects will be generated on the substrate W.

[0035] Furthermore, the laser processing of the first primary surface Wa, unlike the measurement of undulations, can also be performed while the substrate is adsorbed onto the horizontal surface of the stage 31a. Since the amount of surface Wa1 removed is determined by the cumulative irradiation amount, undulations can be reduced. Also, adsorption can prevent the substrate W from shifting position.

[0036] After step S102 above, the transfer arm 38 removes the substrate W from the laser processing module 31 and transfers it to the cleaning module 32.

[0037] Next, the cleaning module 32 brushes and cleans the substrate W (step S103) to remove debris scattered from the irradiation point P of the laser light LB from the substrate W. After step S103, the transfer arm 38 removes the substrate W from the cleaning module 32 and transfers it to the flipping module 36.

[0038] Next, the flipping module 36 flips the substrate W (step S104) so ​​that the second major surface Wb of the substrate W faces upward. After step S104, the transport arm 38 removes the substrate W from the flipping module 36 and transports it again to the undulation measurement module 35. During this process, the substrate W is held horizontally with the second major surface Wb facing upward.

[0039] Next, the undulation measurement module 35 measures the undulation of the second principal surface Wb of the substrate W (step S105). The undulation measurement is performed under natural conditions, such as when the substrate W is simply placed on the horizontal surface of the stage 35a. The displacement meter 35b measures the height distribution of the second principal surface Wb of the substrate W. The undulation measurement module 35 transmits the measurement data to the control module 9. After step S105, the transport arm 38 removes the substrate W from the undulation measurement module 35 and transports it again to the laser processing module 31.

[0040] Next, the laser processing module 31 performs laser processing on the second main surface Wb of the substrate W (step S106). Specifically, the laser processing module 31 irradiates the second main surface Wb with laser light LB, and moves the position of its irradiation point P to cover the entire second main surface Wb, thereby removing the surface layer Wb1.

[0041] By removing the surface layer Wb1, debris attached to the surface layer Wb1 can be removed. Furthermore, by removing the surface layer Wb1, debris that cannot be removed by brushing or other methods can also be removed. Therefore, defects on the substrate W caused by debris can be suppressed.

[0042] Furthermore, the laser processing module 31 can reduce the undulation of the second primary surface Wb when removing the surface layer Wb1. The removal amount is controlled by the product of the output power of the laser light LB (unit: W) and the irradiation time, i.e., the cumulative irradiation amount (unit: J). The greater the cumulative irradiation amount, the greater the removal amount.

[0043] The control module 9 refers to the measurement data of the fluctuation measurement module 35 to control the cumulative irradiation of the laser light LB per unit area of ​​the second principal surface Wb, so as to reduce the fluctuation of the second principal surface Wb. The control system includes one or more of the following: control of the output power of the light source 31b and control of the irradiation time.

[0044] Through this embodiment, since the control module 9 controls the cumulative irradiation per unit area by referring to the measurement data of the fluctuation of the second primary surface Wb under natural conditions, the fluctuation can be effectively reduced and the surface can be effectively corrected.

[0045] The laser processing of the second primary surface Wb is performed under natural conditions, such as simply placing the substrate W on the horizontal surface of the stage 31a. Even if there are foreign objects between the substrate W and the stage 31a, the foreign objects will not be pushed onto the substrate W, and no defects will be generated on the substrate W.

[0046] Furthermore, the laser processing of the second primary surface Wb, unlike the measurement of undulations, can also be performed while the substrate is adsorbed onto the horizontal surface of the stage 31a. Since the amount of surface Wb1 removed is determined by the cumulative irradiation amount, undulations can be reduced. Also, adsorption can prevent the substrate W from shifting position.

[0047] After step S106 above, the transfer arm 38 removes the substrate W from the laser processing module 31 and transfers it to the cleaning module 32 again.

[0048] Next, the cleaning module 32 brushes and cleans the substrate W (step S107) and removes debris scattered from the irradiation point P of the laser light LB from the substrate W. After step S107, the transfer arm 38 removes the substrate W from the cleaning module 32 and transfers it to the etching module 33.

[0049] Next, the etching module 33 etches the substrate W (step S108), reducing the surface roughness of the substrate W or removing the discoloration layer formed by laser irradiation. The etching module 33 may perform wet etching on the substrate W, simultaneously etching the first major surface Wa and the second major surface Wb of the substrate W. Alternatively, the etching module 33 may perform dry etching on the substrate W, sequentially etching the first major surface Wa and the second major surface Wb of the substrate W. After step S108, the transport arm 38 removes the substrate W from the etching module 33 and transports it to the polishing module 37.

[0050] Next, the polishing module 37 polishes the substrate W (step S109) to improve the flatness of the substrate W. The polishing module 37 polishes the first main surface Wa of the substrate W to improve the flatness of the first main surface Wa. The polishing module 37 can also polish the second main surface Wb of the substrate W to improve the flatness of the second main surface Wb. The polishing of the first main surface Wa and the second main surface Wb are performed sequentially, with the substrate W being flipped during the process. The polishing process includes polishing. The order of polishing the substrate W (step S109) and etching the substrate W (S108) can also be reversed. For example, the substrate W can be polished, then both sides of the substrate W can be cleaned, and then the substrate W can be etched. The etching can be two-sided etching or single-sided etching.

[0051] Finally, the transfer arm 38 removes the substrate W from the grinding module 37 and transfers it to the transfer module 34. Then, the transfer arm 24 of the transfer station 2 removes the substrate W from the transfer module 34 and stores the substrate W in the box C on the mounting stage 20.

[0052] Next, referring to FIG6, the laser processing module 31 according to this embodiment will be described. The laser processing module 31 includes, for example, a holding part, i.e., a stage 31a, a light source 31b, and a moving part, i.e., a galvanometer scanner 31c. Furthermore, the laser processing module 31 includes an fθ field mirror 31d, a homogenizer 31e, and an aperture membrane 31f.

[0053] The stage 31a holds the substrate W. For example, the stage 31a holds the substrate W horizontally from below with the main surface of the substrate W to be irradiated by the laser beam LB facing upwards. The stage 31a holds the substrate W in its natural state without adhering to it. Alternatively, the stage 31a in this embodiment may not adsorb the substrate W, but it can also adsorb it. In the latter case, the stage 31a is a vacuum chuck or an electrostatic chuck.

[0054] Light source 31b oscillates laser light LB that is irradiating the top surface (e.g., the first primary surface Wa) of substrate W. Substrate W is absorptive to laser light LB. When substrate W is a silicon wafer, laser light LB is, for example, UV light. Substrate W absorbs laser light LB, either changing from a solid phase to a gaseous phase and scattering, or remaining solid and scattering. As a result, the surface layer Wa1 of the first primary surface Wa of substrate W is removed. Laser light LB can also be focused onto the top surface of substrate W. Irradiation point P is the focusing point with the highest power density in this embodiment. However, irradiation point P may not be a focusing point.

[0055] Light source 31b is, for example, a pulsed laser. The irradiation time of each pulse is, for example, 30 nmsec or less. If the irradiation time of each pulse is less than 30 nmsec, high power density laser light LB can be irradiated onto the substrate W in a short time, suppressing overheating of the substrate W. Therefore, degradation caused by the heat of the substrate W can be suppressed, such as suppressing the formation of a discoloration layer. The irradiation time of each pulse is preferably less than 10 psec. If the irradiation time of each pulse is less than 10 psec, even if the irradiation point P is formed multiple times at the same location, degradation caused by the heat of the substrate W can still be suppressed.

[0056] The galvanometer scanner 31c is, for example, positioned above the substrate W held by the stage 31a. Using the galvanometer scanner 31c, the position of the laser beam LB's irradiation point P on the top surface of the substrate W can be moved without moving the stage 31a. Even when the stage 31a is not attached to the substrate W, as long as the stage 31a remains stationary, there will be no positional shift of the substrate W relative to the stage 31a. Therefore, the position of the irradiation point P can be precisely controlled.

[0057] The galvanometer scanner 31c comprises a combination of two sets (only one set is shown in Figure 6) of laser reflectors 31c1 and galvanometer motors 31c2. One galvanometer motor 31c2 rotates one laser reflector 31c1 and displaces the illumination point P in the X-axis direction. The other galvanometer motor 31c2 rotates the other laser reflector 31c1 and displaces the illumination point P in the Y-axis direction.

[0058] Furthermore, while the moving part in this embodiment is a galvanometer scanner 31c, the technology of the present invention is not limited to this. The moving part may include a polygonal mirror scanner instead of the galvanometer scanner 31c. Compared with the galvanometer scanner 31c, the polygonal mirror scanner has a faster scanning speed and can use higher frequency pulsed lasers. The moving part only needs to move the irradiation point P of the laser light LB to the position of the first principal surface Wa of the substrate W while the substrate W is held on the stage 31a. For example, the moving part may be one that moves the stage 31a in the X-axis and Y-axis directions, and may also have a motor and a ball screw mechanism that converts the rotational motion of the motor into the linear motion of the stage 31a. Furthermore, the moving part may also have a mechanism that rotates the stage 31a about a vertical axis.

[0059] The fθ field lens 31d forms a focal plane perpendicular to the Z-axis direction. During the movement of the irradiation point P in the X-axis or Y-axis direction by the galvanometer scanner 31c, the fθ field lens 31d maintains the Z-axis position of the irradiation point P at the focal plane, and also maintains the shape and size of the irradiation point P within the focal plane. As a result, rectangular irradiation points P can be arranged regularly and without gaps in a two-dimensional arrangement on the top surface of the substrate W, as described below. The height of the irradiation point P is the height of the focal plane.

[0060] The homogenizer 31e system transforms the intensity distribution of the laser light LB from the Gaussian distribution shown in Figure 7(A) to the flat-top distribution shown in Figure 7(B), thereby homogenizing the intensity distribution.

[0061] The aperture membrane 31f shapes the cross-sectional shape of the laser beam LB into a rectangle. The rectangle is not limited to a rectangle, but also includes a square. The aperture membrane 31f is a light-shielding membrane with a rectangular opening. This opening allows, for example, the laser beam LB within the range indicated by arrow D in Figure 7(B) to pass through.

[0062] Through the homogenizer 31e and the aperture membrane 31f, a rectangular irradiation point P with uniform intensity distribution can be formed. By arranging the irradiation point P regularly and without gaps in a two-dimensional manner as described later, the cumulative irradiation amount of laser light LB per unit area can be precisely controlled.

[0063] As shown in Figure 8(A), the irradiation point P is a rectangle with a uniform intensity distribution. Two sides of the rectangle are parallel to the X-axis, and the remaining two sides are parallel to the Y-axis. The X-axis dimension X0 of the irradiation point P can be the same as or different from the Y-axis dimension Y0 of the irradiation point P. This is also the case in Figures 8(B) and 8(C).

[0064] As shown in Figure 8(A), the control module 9 pulses the laser light LB and, during the pulse's pause time, moves the irradiation point P once in the X-axis direction by X0, arranging the irradiation points P in a row without gaps across the entire top surface of the substrate W along the X-axis direction. Then, the control module 9 pulses the laser light LB and repeatedly moves the irradiation point P in the Y-axis direction by Y0 during the pulse's pause time, and again moves the irradiation point P once in the X-axis direction by X0 during the pulse's pause time, arranging the irradiation points P in a two-dimensional arrangement without gaps across the entire top surface of the substrate W.

[0065] Alternatively, as shown in Figure 8(B), the control module 9 pulses the laser light LB and, during the pulse's pause time, moves the irradiation point P halfway along the X-axis direction once, overlapping and arranging the irradiation points P in a row across the entire top surface of the substrate W along the X-axis direction. Then, the control module 9 pulses the laser light LB and repeatedly moves the irradiation point P halfway along the Y-axis direction once during the pulse's pause time, and again moves the irradiation point P halfway along the X-axis direction once during the pulse's pause time, arranging the irradiation points P in a two-dimensional arrangement without gaps across the entire top surface of the substrate W. Furthermore, the control module 9 can pulse the laser light LB and replace "moving the irradiation point P halfway along the Y-axis direction during the pulse's pause time" with "moving the irradiation point P halfway along the Y-axis direction during the pulse's pause time".

[0066] Alternatively, as shown in Figure 8(C), the control module 9 pulses the laser light LB and, during the pulse's pause time, moves the irradiation point P twice in the X-axis direction, forming a gap SP across the entire top surface of the substrate W in the X-axis direction, while simultaneously arranging the irradiation points P in a row. Next, the control module 9 again pulses the laser light LB and, during the pulse's pause time, moves the irradiation point P twice in the X-axis direction, filling the gap SP with irradiation points P. Then, the control module 9 pulses the laser light LB and repeatedly moves the irradiation point P twice in the X-axis direction, once during the pulse's pause time, and once during the pulse's pause time, fills the gap SP with irradiation points P, arranging the irradiation points P in a two-dimensional arrangement without gaps.

[0067] Furthermore, in this embodiment, an fluctuation measurement module 35 and a flipping module 36 are provided separately from the laser processing module 31, but the technology of the present invention is not limited to this. The laser processing module 31 may have the function of the fluctuation measurement module 35. Also, the laser processing module 31 may have the function of the flipping module 36.

[0068] The above describes embodiments of the laser processing apparatus and laser processing method according to the present invention. However, the present invention is not limited to the above embodiments, and various changes, modifications, substitutions, additions, deletions, and combinations can be made within the scope described in the claims. Such modifications, modifications, substitutions, additions, deletions, and combinations are also within the technical scope of the present invention.

[0069] This invention claims priority to Japanese Patent Application No. 2020-151606, filed with the Japan Patent Office on September 9, 2020, and incorporates the entire contents of Japanese Patent Application No. 2020-151606 into this invention.

[0070] 1: Laser processing equipment 2: Moving out and moving in 3: Processing Station 20: Platform 21: Mounting plate 23: Transport Department 24: Moving the arm 31: Laser processing module 31a: Platform 31b: Light source 31c1: Laser reflector 31c2: Galvanometer motor 31c: Galvanometer Scanner 31d:fθ field lens 31e: Uniformer 31f: Orifice membrane 32: Cleaning Module 33: Etching Module 34: Transfer Module 35: Undulation Measurement Module 35a: Platform 35b: Displacement gauge 36: Flip Module 37: Grinding Module 38: Moving arms 91: CPU 92: Recording Media 9: Control Module C: Box G1: Processing Block 1 G2: Second Processing Block G3: Third Processing Block G4: Processing Block 4 G5: Transport Block LB: Laser light P: Irradiation point S101~S109: Steps SP: Gap W: substrate Wa1,Wb1: Surface layer Wa: First Principal Surface Wb: Second primary surface X0, Y0: Length

Claims

1. A laser processing apparatus, comprising: a holding portion for holding a substrate; a light source for oscillating laser light irradiating a first primary surface of the substrate; a moving portion for moving the position of the irradiation point of the laser light on the first primary surface of the substrate while the substrate is held in the holding portion; and a control portion for controlling the light source and the moving portion; the control portion, by controlling the light source and the moving portion, performs laser processing control to irradiate the first primary surface of the substrate held in the holding portion with laser light and reduce the undulation of the first primary surface of the substrate; when performing laser processing control to reduce the undulation of the first primary surface of the substrate, the holding portion holds the substrate in a manner that does not deform it.

2. The laser processing apparatus as described in claim 1, wherein, The control unit refers to the measurement data of the undulation of the first main surface and performs laser processing control to reduce the undulation of the first main surface.

3. The laser processing apparatus as described in claim 2, wherein, The control unit performs laser processing control to reduce the undulation of the first primary surface by referring to the measurement data of the undulation of the first primary surface and controlling the cumulative irradiation of the laser light per unit area of ​​the first primary surface.

4. The laser processing apparatus as described in any one of claims 1 to 3 further includes: a undulation measuring unit, which measures the undulation of the first major surface of the substrate when the stress on the first major surface of the substrate is substantially zero.

5. The laser processing apparatus as described in any one of claims 1 to 3 further includes: a grinding section for grinding the first primary surface after it has been irradiated with laser light.

6. The laser processing apparatus as described in any one of claims 1 to 3 further includes: an etching section for etching the first primary surface after it has been irradiated with laser light.

7. The laser processing apparatus as described in any one of claims 1 to 3 further comprises: a flipping unit for flipping the substrate; and the control unit, after irradiating the first main surface of the substrate with laser light, performing the following actions in sequence: controlling the flipping of the substrate; and controlling the irradiation of laser light on the second main surface opposite to the first main surface of the substrate.

8. The laser processing apparatus as claimed in claim 7 further includes: a grinding section for grinding the second primary surface after it has been irradiated with laser light.

9. The laser processing apparatus as claimed in claim 7 further includes: an etching section for etching the second primary surface after it has been irradiated with laser light.

10. A laser processing method comprising the steps of: holding a substrate by means of a holding portion; and, while holding the substrate by means of the holding portion, irradiating a first primary surface of the substrate with laser light and reducing the undulation of the first primary surface of the substrate; wherein, during the laser processing to reduce the undulation of the first primary surface of the substrate, the holding portion holds the substrate in a manner that does not deform the substrate.

11. The laser processing method as described in claim 10 further includes the following steps: performing laser processing to reduce the undulation of the first primary surface by referring to measurement data of the undulation of the first primary surface.

12. The laser processing method as claimed in claim 11 further includes the following steps: performing laser processing to reduce the undulation of the first primary surface by referring to measurement data of the undulation of the first primary surface and controlling the cumulative irradiation of the laser light per unit area of ​​the first primary surface.

13. The laser processing method according to any one of claims 10 to 12 further comprises the following step: measuring the undulation of the first major surface of the substrate while the stress on the first major surface of the substrate is substantially zero.

14. The laser processing method as described in any one of claims 10 to 12 further comprises the step of: grinding the first primary surface after irradiation with the laser light.

15. The laser processing method as described in any one of claims 10 to 12 further comprises the step of etching the first primary surface after it has been irradiated with laser light.

16. The laser processing method according to any one of claims 10 to 12, after irradiating the first main surface of the substrate with laser light, sequentially includes the following steps: flipping the substrate; and irradiating a second main surface opposite to the first main surface of the substrate with laser light.

17. The laser processing method as described in claim 16 further includes the step of: grinding the second primary surface after it has been irradiated with laser light.

18. The laser processing method as described in claim 16 further comprises the step of etching the second primary surface after it has been irradiated with laser light.

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